Long-term Objectives: To develop a high-titer anti-West Nile virus immune globulin preparation (WNIG) as an effective first line countermeasure to West Nile Virus (WNV) infections. On completion of this project we expect to be ready to commence the testing of WNIG in humans. Israeli plasma will be screened and plasma with antibodies to WNV will be collected. Since WNV is endemic in Israel and non-specific Israeli IVlG has already been used with some success in treating infected patients, the resulting WNIG is expected to contain high-titer WNV immunoglobulins and may be used as an emergency prophylactic as well as an effective treatment. Later in the project WNIG will be developed from American plasma. Specific Aim #1: Develop enriched WNIG by screening and selection for IgG positive plasma, fractionation and characterization: WNIG will be derived from Israeli plasma donations testing positive by ELISA for WNV IgG. The result will be at least 10 times more potent than the preparation (Omr-lgG-am) currently used in an NIH clinical study and emergency cases. Specific Aim #2: Test the efficacy of the enriched WNIG and achieve supportive clinical information for various routes of infection: In-vivo models will test increased potency. Initial animal tests will be in mosquito transmission of WN encephalomyelitis. Other routes of infection will include transplantation and breast-feeding. Specific Aim #3: Improve the screening method for the selection of convalescence (or vaccinated) plasma donors that have high titers of neutralization antibodies: Preliminary research indicates that some samples exhibit high binding and low neutralization (and vice versa). Short recombinant peptides will be used to isolate antibodies that bind to specific sites resulting in virus neutralization. This will enable high throughput ELISA to be used to select plasma donations with specific binding to high neutralization sites. Specific Aim #4: Identify US subjects with WNV antibodies, select plasma donors and develop a US plasma-derived enriched WNIG: Approaches used in Specific Aims #1-3 will be used to develop a US plasma-derived WNIG. In the absence of sufficient WN antibodies in convalescent donors, hyper-immune donors treated with an attenuated vaccine may be explored as an alternative source of plasma. [unreadable] [unreadable]